Analysis of hygrothermal parameters in Finnish and Lithuanian multi-family buildings before and after energy retrofits

This study focuses on analyzing temperature- and moisture-related parameters based on data from 45 Finnish and 20 Lithuanian multi-family buildings. The data consist of two rounds of 2-month data-logging (1-h interval) of indoor temperature and relative humidity at two locations: one representing average occupied zone and the other one nearby the coldest spot of the building envelope. Between the two rounds of data-logging, 37 buildings from Finland and 15 buildings from Lithuania underwent retrofits, aiming to improve their energy efficiency. Measurement data were coupled with outdoor data from national weather stations, based on which a temperature factor ( f_c) and excess indoor moisture content (Δ v) were calculated. Based on the results, f_cwas significantly higher in Lithuanian case buildings after the retrofits, whereas no significant differences were observed in Finnish buildings. In addition, Δ v was significantly lower in Finnish case buildings after retrofits, whereas an opposite trend was seen in the Lithuanian buildings.